THE COMSTOCK LODE. 83 



charged with sulphates of copper and magnesia. Pyromorphite also occurred 

 in the Middle Ophir. The powdered eastern quartz-mass was often held 

 together by thick accumulations of ore, which were traversed in every direc- 

 tion by wires of native silver; especially was this the case in the upper levels 

 of the Mexican. The arrangement of the minerals in the north part of the 

 Ophir bonanza was very interesting. From the surface down to 60 feet below 

 the Walsh tunnel, the galena, copper, and iron pyrites, with a little blende, 

 predominated. From that point down to the great curve of the east wall, 

 rich masses of the ordinary Comstock silver ore gave an immense value 

 to the quartz. Thence to the bottom iron pyrites and blende gradually 

 replaced the silver ore. ' In the Ophir bonanzas, more malleable sulphide 

 of silver occurred than anywhere else in the Comstock. It is held to be an 

 earlier product than the brittle minerals, and often performed the duty of 

 holding together the fractured quartz. The red quartz body back of the first 

 Ophir horse contained very little within the Ophir claim; but on the south, 

 where it entered the California, was charged with a large body of base ores. 

 Beginning at the 150-foot level, it extended down nearly to the Latrobe tunnel, 

 and in a longitudinal direction stretched from the north line of the California 

 claim 150 feet south; its general thickness was 60 feet. This body never 

 averaged over $10 to $12 per ton, and was made up of blende, iron pyrites, 

 and galena, the total value *of silver being contained in the latter mineral. 



From the position of the clay -veins, and the, manner in which they not 

 not only separate the quartz from the walls and horses, but in which they 

 surround even the bottom of the sheets, it is evident that they were formed 

 subsequently to the quartz periods. This is further shown by the fact that 

 they contained rolled pebbles of quartz ; yet it is singular that none of 

 these pebbles ever carry an appreciable quantity of silver ore. The clays 

 are undoubtedly formed by the decomposition of the propylite material, and 

 it is only natural that where they form a contact with the bonanza that the 

 clay itself should be more or less charged with ore. Wherever examined 

 in the immediate neighborhood of these bodies, it has been found to be 

 charged with silver, from a trace up to a considerable percentage. At 

 one place in the Grould and Curry the clay yielded $5 99 of silver to the 

 ton. Near the Potosi strike in the Savage, it is found to carry $8 10 to the 



